The Heritage Audio 8173 is the most versatile design in a 8 3/4 in module format. 80dB gain preamp coupled with a 4 band equalizer.
When launched in 1972, the 1081 became the most flexible equalizer ever in a mixing console. Its 4 band equalizer allowed sculpting the sound in such a unique way, mainly due to the fact that both mid bands covered almost the whole audio spectrum in 20 steps. Unfortunately, a class A/B output stage was used instead of the class A one used in the 1073, making it a second choice for tracking in favour of the 1073.
Being users of the old modules for 20 years, we always came with the "could it be possible to have a 1081 eq with a 1073 preamp in our console" question. The answer has been NO, until now...
We are proud to introduce the 8173 mic pre- 4 band equalizer module. The name says it all. The best of both worlds in an 8 3/4" module package, fully compatible with Series 80 consoles. It could be easily described as a 1073 with the mid bands of the 1081. We´ve decided to keep the 1073 Baxandall shelving lo and hi eq bands as they sound amazing, but have implemented a choice of 3 hi shelving frecuencies, a la 1084. Flexibility and Tone!!!
80dB Class A Microphone preamplifier, HI-LO selectable minimum input impedance, balanced and floating. High gain positions show a higher impedance, ideal for old ribbon mics.
10dB Class A Line Amplifier, Bridging input impedance, balanced and floating.
Class A, single ended, 2N3055 driven high headroom output stage.
High Frequency: +/-16dB selectable frequency shelving at 10, 12 or 16 kHz, Baxandall type.
Low Frequency: +/-16dB with selectable frequency shelving of 35Hz, 60Hz, 110Hz & 220Hz ,Baxandall type.
1081 Upper Mid Frequency: +/-18dB peaking, fixed 'Q' , selectable centre frequencies of 1.5Khz, 1.8kHz, 2.2Khz, 2.7kHz, 3.3Khz, 3.9kHz, 4.7kHz, 5.6kHz , 6.8kHz and 8.2Khz , inductor based.
1081 Lower Mid Frequency: +/-18dB peaking, fixed ´Q´, selectable center frequencies of 220Hz, 270Hz, 330Hz, 390Hz, 470Hz, 560Hz, 680Hz, 820Hz, 1000Hz and 1200Hz, , inductor based.
High Pass Filter: 18dB per octave slope, switchable between 50Hz, 80Hz & 300Hz, inductor based. (Although push button switches has been used instead of the classic rotary switch, the circuit is the same exact one found in vintage 1073s, sacrificing only one frequency choice for space issues .Real state is tight inside these modules).
EQ Button: Switches the equalizer on or off.
Phase Button: Flips phase180º.
Microphone input impedance: HI, 1200 Ohm minimum, LO, 300 Ohm minimum. Higher gain positions gradually have greater impedances, optimum for lo gain ribbon mics. Input is transformer balanced and floating.
Line input impedance: 10KOhms bridging, transformer balanced and floating.
Output impedance: Less than 75 Ohms, transformer balanced and floating, to drive a load of 600 Ohms.
Maximum output: Greater than +26dBm into 600 Ohms, greater than +32dBu into 10KOhms.
THD: Less than 0.025% at 1Khz, Less than 0.05% at 100Hz.
Frequency response :20Hz (+0.3dB) to 20Khz (-0.2dB).